Datasheet

NXP Semiconductors
PCF8574; PCF8574A
Remote 8-bit I/O expander for I
2
C-bus with interrupt
© NXP B.V. 2013. All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [e-mail]
Date of release: 27 May 2013
Document identifier: PCF8574_PCF8574A
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
24. Contents
1 General description. . . . . . . . . . . . . . . . . . . . . . 1
2 Features and benefits . . . . . . . . . . . . . . . . . . . . 1
3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4 Ordering information. . . . . . . . . . . . . . . . . . . . . 2
4.1 Ordering options . . . . . . . . . . . . . . . . . . . . . . . . 2
5 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
6 Pinning information. . . . . . . . . . . . . . . . . . . . . . 4
6.1 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
7 Functional description . . . . . . . . . . . . . . . . . . . 5
7.1 Device address. . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1.1 Address maps. . . . . . . . . . . . . . . . . . . . . . . . . . 5
8 I/O programming . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1 Quasi-bidirectional I/Os . . . . . . . . . . . . . . . . . . 6
8.2 Writing to the port (Output mode) . . . . . . . . . . . 8
8.3 Reading from a port (Input mode) . . . . . . . . . . 9
8.4 Power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.5 Interrupt output (INT
) . . . . . . . . . . . . . . . . . . . 10
9 Characteristics of the I
2
C-bus . . . . . . . . . . . . 11
9.1 Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1.1 START and STOP conditions . . . . . . . . . . . . . 11
9.2 System configuration . . . . . . . . . . . . . . . . . . . 11
9.3 Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . 12
10 Application design-in information . . . . . . . . . 13
10.1 Bidirectional I/O expander applications . . . . . 13
10.2 How to read and write to I/O expander
(example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.3 High current-drive load applications . . . . . . . . 14
10.4 Migration path. . . . . . . . . . . . . . . . . . . . . . . . . 14
11 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 15
12 Thermal characteristics . . . . . . . . . . . . . . . . . 15
13 Static characteristics. . . . . . . . . . . . . . . . . . . . 16
14 Dynamic characteristics . . . . . . . . . . . . . . . . . 17
15 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 19
16 Handling information. . . . . . . . . . . . . . . . . . . . 22
17 Soldering of SMD packages . . . . . . . . . . . . . . 22
17.1 Introduction to soldering . . . . . . . . . . . . . . . . . 22
17.2 Wave and reflow soldering . . . . . . . . . . . . . . . 22
17.3 Wave soldering. . . . . . . . . . . . . . . . . . . . . . . . 22
17.4 Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 23
18 Soldering of through-hole mount packages . 24
18.1 Introduction to soldering through-hole mount
packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
18.2 Soldering by dipping or by solder wave . . . . . 24
18.3 Manual soldering . . . . . . . . . . . . . . . . . . . . . . 24
18.4 Package related soldering information. . . . . . 25
19 Soldering: PCB footprints . . . . . . . . . . . . . . . 26
20 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . 28
21 Revision history . . . . . . . . . . . . . . . . . . . . . . . 29
22 Legal information . . . . . . . . . . . . . . . . . . . . . . 31
22.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 31
22.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
22.3 Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . 31
22.4 Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . 32
23 Contact information . . . . . . . . . . . . . . . . . . . . 32
24 Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33